Abstract: This paper uses longitudinal data from two informal settlements of Nairobi, Kenya to examine patterns of child growth and how these are affected by four different dimensions of poverty at the household level namely, expenditures poverty, assets poverty, food poverty, and subjective poverty. The descriptive results show a grim picture, with the prevalence of overall stunting reaching nearly 60% in the age group 15–17 months and remaining almost constant thereafter. There is a strong association between food poverty and stunting among children aged 6–11 months (p<0.01), while assets poverty and subjective poverty have stronger relationships (p<0.01) with undernutrition at older age (24 months or older for assets poverty, and 12 months or older for subjective poverty). The effect of expenditures poverty does not reach statistical significant in any age group. These findings shed light on the degree of vulnerability of urban poor infants and children and on the influences of various aspects of poverty measures. Highlights: We assess how infant and child undernutrition varies across four dimensions of poverty status. There is a strong association between food poverty and stunting among children aged 6–11 months. Assets poverty and subjective poverty have stronger effects on undernutrition at older age. The effect of expenditures poverty does not reach statistical significant in any age group. These findings suggest the need to design and scale up nutrition interventions among the urban poor.